In conventional motor vehicles, air flow to the heat exchanger is controlled by way of adjustable elements in order to enhance the warm-up behaviour of the engine. The adjustable elements, the closing elements, usually involve a plurality of pivotally supported louvres, these being arranged with their axes of rotation parallel to one another and rotatably arranged altogether in a frame. The frame with the louvre arrangement is positioned behind the radiator grille and in front of the engine heat exchanger. Such an arrangement may also be arranged in a flow duct, via which cooling air is fed from an opening arranged in the vehicle body to the heat exchanger, the engine radiator. By closing the fresh air feed during the warm-up phase and by controlling the quantity of cooling air in accordance with the engine temperature, the optimum operating temperature is reached more rapidly and can be kept within a tight temperature range.
Examples of the devices described are disclosed in EP 2 233 341 A1, EP 2 233 342 A1, EP 2 325 035 A1, DE 10 2008 049 010 A1, DE 20 2005 010 683 U1 and DE 60 2004 007 338 T2.
DE 10 2009 014 003 A1 discloses an actuator, which switches the air inlet into the open position when a predefined temperature is exceeded. The system described does not afford a simple, reliable opening of the air inlet. Finally, this known solution also does not comprise any safeguard against drive-side malfunctions.